/* ============================================================
   stack.css — page skeleton: topbar, nav, sections, footer
   ============================================================ */

.topbar {
    background: var(--bg);
    border-bottom: 0.0625rem solid var(--ln);
    position: sticky;
    top: 0;
    z-index: 20;
}

.topbar__row {
    align-items: center;
    display: flex;
    justify-content: space-between;
    min-height: 4rem;
}

.site-logo {
    align-items: center;
    display: flex;
    gap: 0.625rem;
    text-decoration: none;
}

.site-logo:hover {
    background: transparent;
    color: inherit;
}

.site-logo__mark {
    flex: 0 0 auto;
}

.site-logo__name {
    font-family: 'Alegreya', Georgia, serif;
    font-size: 1.375rem;
    font-weight: 700;
    letter-spacing: 0.01em;
}

.topbar__side {
    align-items: center;
    display: flex;
    gap: 0.875rem;
}

.topbar__enter {
    font-size: 0.875rem;
    padding: 0.4375rem 1rem;
}

.hamburger {
    background: none;
    border: 0.0625rem solid var(--fg);
    cursor: pointer;
    display: inline-flex;
    flex-direction: column;
    gap: 0.3125rem;
    padding: 0.625rem 0.5625rem;
    position: relative;
    z-index: 40;
}

.hamburger__bar {
    background: var(--fg);
    display: block;
    height: 0.125rem;
    transition: transform 0.2s, opacity 0.2s;
    width: 1.375rem;
}

.hamburger.toggled .hamburger__bar:nth-child(1) {
    transform: translateY(0.4375rem) rotate(45deg);
}

.hamburger.toggled .hamburger__bar:nth-child(2) {
    opacity: 0;
}

.hamburger.toggled .hamburger__bar:nth-child(3) {
    transform: translateY(-0.4375rem) rotate(-45deg);
}

.mainnav {
    background: var(--dk);
    display: none;
}

.mainnav.toggled {
    display: block;
    inset: 0;
    overflow-y: auto;
    position: fixed;
    z-index: 10;
}

.mainnav__list {
    display: flex;
    flex-direction: column;
    gap: 0;
    list-style: none;
    margin-bottom: 0;
    padding: 5.5rem 1.5rem 2rem;
}

.mainnav__link {
    border-bottom: 0.0625rem solid rgba(255, 255, 255, 0.15);
    color: var(--bg);
    display: block;
    font-size: 1.25rem;
    padding: 1rem 0.25rem;
    text-decoration: none;
}

.mainnav__link:hover {
    background: var(--ac);
    color: var(--dk);
}

.section {
    border-bottom: 0.0625rem solid var(--ln);
    padding-bottom: 4rem;
    padding-top: 4rem;
}

.section--flush {
    padding-bottom: 0;
    padding-top: 0;
}

.section__head {
    margin-bottom: 2.5rem;
    max-width: 44rem;
}

.section__more {
    margin-bottom: 0;
    margin-top: 2rem;
}

.footer {
    background: var(--bg);
    border-top: 0.1875rem solid var(--fg);
    padding-bottom: 1.75rem;
    padding-top: 1.75rem;
}

.footer__row {
    align-items: center;
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem 1.75rem;
    justify-content: space-between;
}

.footer__grid {
    display: grid;
    gap: 2.25rem;
    padding-bottom: 2.5rem;
}

.footer__brand p {
    color: var(--mut);
    font-size: 0.9375rem;
    margin: 0.875rem 0 0;
    max-width: 18rem;
}

.footer__col h3 {
    font-family: ui-monospace, 'Cascadia Mono', Consolas, monospace;
    font-size: 0.75rem;
    font-weight: 400;
    letter-spacing: 0.1em;
    margin-bottom: 1rem;
    text-transform: uppercase;
}

.footer__col ul {
    display: grid;
    gap: 0.5rem;
    list-style: none;
    margin: 0;
    padding: 0;
}

.footer__col a {
    font-size: 0.9375rem;
    text-decoration-color: var(--ln);
}

.footer__base {
    align-items: center;
    border-top: 0.0625rem solid var(--ln);
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem 1.75rem;
    justify-content: space-between;
    padding-top: 1.75rem;
}

.footer__links {
    display: flex;
    flex-wrap: wrap;
    gap: 0.25rem 1.25rem;
    list-style: none;
    margin: 0;
    padding: 0;
}

.footer__links a {
    font-size: 0.9375rem;
    text-decoration-color: var(--ln);
}

.footer__note {
    color: var(--mut);
    font-size: 0.875rem;
    margin: 0;
}

@media (min-width: 48rem) {
    .topbar {
        position: static;
    }

    .footer__grid {
        grid-template-columns: 1.4fr 1fr 1fr 1fr;
    }

    .hamburger {
        display: none;
    }

    .mainnav {
        background: var(--bg);
        border-bottom: 0.0625rem solid var(--ln);
        display: block;
    }

    .mainnav__list {
        display: flex;
        flex-direction: row;
        gap: 0;
        padding: 0;
    }

    .mainnav__link {
        border-bottom: none;
        border-right: 0.0625rem solid var(--ln);
        color: var(--fg);
        font-family: ui-monospace, 'Cascadia Mono', Consolas, monospace;
        font-size: 0.8125rem;
        letter-spacing: 0.08em;
        padding: 0.75rem 1.25rem;
        text-transform: uppercase;
    }

    .mainnav__list > li:first-child .mainnav__link {
        border-left: 0.0625rem solid var(--ln);
    }
}